The second-largest Ebola outbreak in history has entered its second year. It has taken more than 1,900 lives and shows no signs of abating. Compared with West Africa’s outbreak in 2014-15, which spread like wildfire, the current one in eastern Congo is more of a slow burn. Disease hunters discover around 10 new infections per day. Since children are disproportionately infected, the mortality rate is high. For every infected person who survives the disease, two will die of it.

This crisis may seem less significant because the memory of West Africa’s suffering looms so large. That earlier outbreak was supercharged by jumping to the large coastal cities of Freetown, Monrovia and Conakry. So far, the outbreak in Congo has been confined to smaller population hubs such as Beni, Butembo, Katwa and Mangina. Cases in the bigger city of Goma have been contained.

But the situation is groundbreaking in a different way. Because of the outbreak’s longevity and durability, it raises the prospect that one of the most dangerous threats to humanity could become endemic.

Experts are still pondering why this outbreak smolders rather than rages. One possible answer, according to Steve Morrison of the Center for Strategic and International Studies, is that “the international response is containing it even while failing to arrest it.”

On the plus side, the response is larger (about 1,200 health professionals on the ground), better trained and more experienced than in 2014-15. The World Health Organization’s emergency response has improved. An effective Ebola vaccine has been given to roughly half the contacts traced to specific infections, as well as to health workers involved in the response.

On the negative side, this is a health campaign conducted in a war zone. More than 100 different militias roam eastern Congo. Armed groups rape, exploit and murder with impunity. The Congolese military has sometimes joined in the general cruelty. The region’s traumatized civilians are naturally suspicious of outsiders. Local politicians spread rumors that Ebola is a myth created by the government, or a disease purposely imported by foreigners. Health workers attempting to identify cases, trace contacts and put infected people in isolation have been attacked and killed. The U.S. government has deemed it too dangerous to have its own health officials on the front lines of the effort.

The Congolese response is now under the direction of a respected health minister, Dr. Jean-Jacques Muyembe, who believes that improved community engagement might mitigate the security situation. But eastern Congo is a long, long way from the capital in Kinshasa, and the central government often lacks local power and legitimacy.

U.S. government health officials believe the next few months will be critical to see if Muyembe’s approach has results. One American health expert I spoke with, however, was not hopeful. “The outbreak is not under control,” he said, “and there is no coherent plan to establish control. … The Congolese won’t fix this. That much is clear.”

Even if the outbreak were contained to its current geography, endemic Ebola would raise terrible risks. Infected people can spread the disease sexually for months after they recover. Like HIV, it can pass from pregnant mothers to their unborn children.

And there is no guarantee that the disease would stay contained. It could easily spread to neighboring Uganda, Rwanda or South Sudan. It could emerge in African capitals. Or it could make its way to Western countries.

If the current outbreak remains uncontrolled, the next steps are far from clear. Most health experts think that going in with guns to protect health workers would make matters worse. More funding for international organizations and NGOs might allow for a broader mix of services and a larger supply of vaccines.

Ultimately, however, the Congo outbreak demands a redefinition of America First. When it comes to disease, the frontiers of the country’s security can’t be drawn at ports and airports. The safety of Americans may be determined by the success of disease control in the far reaches of the Democratic Republic of Congo. And this may require the return of American health personnel to the front lines of the Ebola fight. And this may further require the U.S. to take the lead in seeking answers to the chaos and violence in eastern Congo. And all this would depend on a type of presidential leadership we haven’t recently seen but desperately need.